微纳米RDX炸药的连续比热容、热力学性质和热分解动力学
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摘要
为了分析不同粒径RDX的热性能,在温度288～353K下,采用μSC量热法测试了粒径分别为1μm、500nm、100nm的微纳米R D X炸药的连续比热容,由比热容随温度的变化曲线拟合得到了温度二次方的Cp表达式,并依据热力学定律计算获得了不同粒径RDX的热力学参数;采用DSC分别测试了3种粒径RDX的热分解性能,获得热分解规律曲线,并用Kissinger法计算了不同粒径RDX的分解动力学参数。结果表明,μSC量热法测试连续比热容简便并且数据准确。微纳米RDX的比热容、熵和焓均随着温度的升高而增加,但吉布斯自由能降低;焓和吉布斯自由能随粒径的下降而下降,但熵随着粒径的下降而增加;与微米RDX相比,两种纳米RDX的熵和吉布斯自由能随粒径的变化不大,这两种热力学函数显示了纳米与微米材料之间的不同;纳米与非纳米RDX熔融态分解的动力学参数虽有不同,但它们都服从同一"动力学补偿效应"。
In order to analyze the thermal properties of R DX with different particles sizes, the continuous specific heat capacities of micro-sized and nano-sized RDX with particle size of 1μm, 500 nm and 100 nm were determined by the μSC calorimetry method at the temperature of 288-353 K. The specific heat capacity curves were fitted to achieve the equation of Cp, and the thermodynamic properties of RDX with different particle sizes were calculated based on the thermodynamic lawThe thermal decomposition behaviors of RDX with different particle sizes were investigated by DSC and their decomposition kinetic paramelers were calculated according to the Kissinger's method. The results showthat the μSC calorimetry method is favorable for the measurement of specific heat capacity with simplicity and high accuracy. For the micro-sized RDX particles, the specific heat capacity, entropy and enthalpy increase with the increase in temperature, whereas the Gibbs free energy shows an opposite behavior. Moreover, the enthalpy and Gibbs free energy of RDX reduce with the decrease in particle sizes, but the entropy increases with the decrease in sizes. Compared with the micro-sized R DX, the changes occurred to entropy and Gibbs free energy of nano-sized RDX are relatively small, which is believed to originate from their smaller particle size. Although kinetic parameters of the melting and deco mpo sition pro cesses of micro-sized and nanosized RDX are different, they all obey the "dynamic compensation effect" rule.
In order to analyze the thermal properties of R DX with different particles sizes, the continuous specific heat capacities of micro-sized and nano-sized RDX with particle size of 1μm, 500 nm and 100 nm were determined by the μSC calorimetry method at the temperature of 288-353 K. The specific heat capacity curves were fitted to achieve the equation of Cp, and the thermodynamic properties of RDX with different particle sizes were calculated based on the thermodynamic lawThe thermal decomposition behaviors of RDX with different particle sizes were investigated by DSC and their decomposition kinetic paramelers were calculated according to the Kissinger's method. The results showthat the μSC calorimetry method is favorable for the measurement of specific heat capacity with simplicity and high accuracy. For the micro-sized RDX particles, the specific heat capacity, entropy and enthalpy increase with the increase in temperature, whereas the Gibbs free energy shows an opposite behavior. Moreover, the enthalpy and Gibbs free energy of RDX reduce with the decrease in particle sizes, but the entropy increases with the decrease in sizes. Compared with the micro-sized R DX, the changes occurred to entropy and Gibbs free energy of nano-sized RDX are relatively small, which is believed to originate from their smaller particle size. Although kinetic parameters of the melting and deco mpo sition pro cesses of micro-sized and nanosized RDX are different, they all obey the "dynamic compensation effect" rule.
引文
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[2]Subramanian,Shanthi,Tiegs,et al.Nanoporous silicon based energetic materials,AD A506071[R].Springfield:N TIS,2008.
[3]Risse B,et al.Synthesis and desensitization of nano-β-HMX[J].Propellants,Explosives,Pyrotechnics,2014,39:397-401.
[4]Rossi C.Two decades of research on nano-energetic materials[J].Propellants,Explosives,Pyrotechnics,2014,39:323-327.
[5]Qiu H W,Stepanov V,Di Stasio A R,et al.RDX-based nanocomposite microparticles for significantly reduced shock sensitivity[J].Journal of Haz ardous Materials,2011,185:489.
[6]Siviour C R,Gifford MJ,Walley S M,et al.Particle size effect on the mechanical properties of a polymer bonded explosive[J].Journal of Materials Science,2004,39:1255.
[7]李兆娜,马海霞,宋纪蓉,等.NTO的比热容、热力学性质及绝热至爆时间[J].火炸药学报,2008,31(3):25-28.LI Z hao-na,MA Hai-xia,SO N G Ji-rong,et al.Specific heat capacity,thermodynamic properties and adiabatic time-to-explosion of N TO[J].C hinese Journal of Explosives&Propellants(Huoz hayao Xuebao),2008,31(3):25-28.
[8]胡哲,江劲勇,路桂娥,等.改黑碳推进剂比热容和热导率与温度之间的关系[J].火炸药学报,2015,38(6):95-98.HU Z he,JIAN G Jin-yong,LU Gui-e,et al,Temperature dependence of specific heat capacity and thermal conductivity of GHTpropellant[J].C hinese Journal of Explosives&Propellants(Huoz hayao Xuebao),2015,38(6):95-98.
[9]刘子如,含能材料热分析[M].北京:国防工业出版社,2008
[10]Cheng S Z D.Handbook of Thermal Analysis and Calorimetry[M].Amsterdam:Elsevier Science,2002.
[11]Wunderlich B.Thermal Aalysis.[M].Boston:Academic Press,1990.
[12]徐抗震,常春藤,宋纪蓉,等.RDX的比热容、热力学性质及绝热至爆时间[J].火炸药学报,2008,31(4):35-38.XU Kang-zhen,C HAN G C hun-teng,SO N G Ji-rong,et al.Specific heat capacity,thermodynamic properties and adiabatic time-to-explosion of R D X[J].C hinese Journal of Explosives&Propellants(Huoz hayao Xuebao),2008,31(4):35-38.
[13]Brill TB,Gongwer P E,Williams G K.Thermal decomposition of energetic materials 66.Kinetic compensation effects in HMX,R DX and NTO[J].J Phys C hem,1994,98:12242-12247.